RealBadAngel/technic — pull request #7 by khonkhortisan (2013-02-21 19:55:47+00:00)
Title: Keep players from falling through moving frames

Before, when a frame moved, it removed the whole thing, then reappeared in its new location. If it takes any time at all to do this, a player will fall while the machine doesn't exist, then be stuck inside the machine or completely under it when it reappears.
Now, when a frame moves, it creates a copy in its new location, then removes any part of the original that wasn't overwritten by the copy. This way, the machine still exists, and a wave of duplication goes through it, followed by a wave of deletion.

Here's a textual demonstration:

P represents the player, other letters represent frames and nodes moved by frames, and - represents the ground.

```
Before:

----
P
ABCD

----

P
ABC

----
P
AB

----
P
A

----

P

----

D
P
----

CD
P
----

BCD
P
----

ABCD
P
----
```

```
After:

----
P
ABCD

----
P
ABCDD

----
P
ABCCD

----
P
ABBCD

----
P
AABCD

----
P
ABCD

----